The problem with racists is that generally speaking, they are really, really stupid. Anyone with an elementary understanding of biology and genetics knows that the concept of 'race' is almost completely meaningless. The notion that one race is superior to another makes as much sense as saying people with brown eyes are better than people with blue eyes. Skin pigment varies according to a population's exposure to the sun - nothing more, nothing less. White isn't 'better' than black, or black better than brown. It's just better adapted to particular environments.
Sadly white supremacist Craig Cobb, a North Dakotan who has dedicated his life to preserving the 'purity of the white race', wasn't bright enough to understand this extremely basic concept. So you can imagine the surprise he got when confronted with DNA evidence that he is in fact, 14% Subsaharan African on the Trisha Goddard Show.
Looks like that whites only town he has been trying to create in Leith, ND, may have to go on hold.